Maybe it's because some middle and low class people have ambition and aspirations of being rich, and don't want the government putting in place barriers to competition and opportunity that the current rich enjoyed on their way to realizing their dream. It's part of the reason I despise the hypocrite Warren Buffett. He has his money, won't pay the IRS back taxes, talks about how he isn't paying enough, refuses to voluntarily write a check, and favors legislation that would prevent others from having the same system opportunity that he took advantage of to make his money. I don't care how much money someone has, I just want the same opportunity to achieve the way they did, and the government is constantly seeking to limit this.
And the democrats think that they're the ones who champion the poor and middle class? Their legislation ensures that more and more people STAY poor and in the middle class.